Sparking device.



No. 746,406. PATENT-ED DEC. 8, 1903. J. S. THURMAN.

SPARKING DEVICE.

APPLICATION FILED FEB. 9, 1903. N0 MODEL. 2 SHEETS-SHEET l- JUW No. 746,406. PATENTED DEC. 8. 1903.

' J. S. THURMAN.

SPARKING DEVICE.

APPLICATION FILED FEB. 9. 1903. N0 MODEL. 2 SHEETS-SHEET 2.

Patented December 8, 1903.

PATENT OFFICE.

JOHN S. THURMAN, OF ST. LOUIS, MISSOURI.

SPARKING DEVICE.

SPECIFICATION forming part of Letters Patent No. 746,406, dated December 8, 1903.

Application filed February 9, 1903. Serial No. 142,556. (No model.)

To all whom it may concern.- Be it known that I, JOHN S. THURMAN, a citizen of the United States, residing at St.

, Louis, Missouri, have invented a certain new 1 make and use the same, reference being had to the accompanying drawings, forming part of this specification, in which-- Figure 1 is a side elevational view of my improved sparking device. Fig. 2 is an end elevational'view looking from the outside. Fig. 3 is a partial end elevational view looking from the inside. Fig. 4 is a detail view of the means for operating the tripping-dog. Fig. 5 is a sectionalview on line 5 5, Fig. 3. Fig. 6 is an end elevational view of an enginecylinder, showing my improved sparking device mounted thereon. Fig. 7 is a detailed perspective View of the movable contact, its shaft, and fixed arm; and Fig. 8 is a detailed perspective view of the arm, which is designed to be loosely mounted on the shaft.

This invention relates to a new and useful improvement in a sparking device for gasengines, the object being to mount the moving parts on a removable base, which can be inserted and removed into and from the cylinder of the engine readily for purposes of repair and adjustment, also to simplify the construction of the parts and to provide means whereby the wear between the contactpoints will be automatically taken up. With these objects in view the invention consists in the construction, arrangement,

and combination of the several parts, all as will hereinafter be described and afterward pointed out in the claims.

In the drawings, 1 indicates a base-plate having an inwardly-extending projection or boss 2, designed to project through the wall of the cylinder in which the sparking device is mounted. I

3 is a fixed terminal in the form of a bolt mounted in the boss 2 and insulated from-the same, the outer end of this bolt being threaded to receive nuts 4, by which it is held in posit-ion, these nuts serving as a binding-post for one of the circuit-wires.

- 5 indicates a rocking terminal having an arm 6 on its inner end, which arm is designed to make and break the circuit by contacting with and being disengaged from the inner head of the fixed terminal 3. Means are provided for rocking the movable terminal 6, said means consisting of an arm 7, fixed on the outer end of the shaft 5 and provided with a lateral lug or extension 8, designed to contact with an insulation-block 9, mounted in a boss 10, which insulation-block also serves as a bufier.

11 indicates an arm loosely mounted on the shaft 5, one member of said arm moving in the path of the projection 8 and being provided with an extension 12, preferably made of tool-steel, which extension is secured to the arm. This arm could be formed of one piece, the extension being integral therewith; but for the sake of cheapness and to insure a longer life to the device I preferably use the tool-steel extension. The lower member of this arm 13 is provided with a teat to center a compression-spring 14, said spring being seated in a barrel 15, preferably integral with the base-plate l. A screw-plug 16 is introtroduced into the end of the barrel for adjusting the resistance of the spring 14.

Arm 11 is provided with an extension 17 at its upper end, which extension affords a support for one end of a tension-spring 18, the other end of said spring being connected to the upper end of arm 7.

The construction just described insures the normal separation of the contacts 3 and 6 due to the pressure of spring 14. The spring 18 serves onlyto hold the arms 7 and 11 together, so that they can move in unison until the arm 7 is arrested by the terminal 6 contacting with the terminal 3. Arm 11 is then permitted to continue its movement. This movement of arm 11 places the spring 14 under greater compression and the spring 18 under greater tension. Thus the contact 6 is yieldingly held against the contact 3, and any wear between the contacts will in this manner be taken up. If when arm 11 is retracted and the springs 14 and 18 are under free to return to its normal position under the influence of both springs, said arm will return and in so doing strike the lateral projection 8 on the arm 7 and quickly move the contact 6 away from the contact 3, producing a spark.

One of the circuit-terminals is the contact 3, as before stated, and the other circuit-terminal is the casing of the engine, which is in electrical connection with the contact 6. In this connection the strength of the current and the arrangement of the sparking-coils are of course in harmony with the objects sought to be obtained.

The means for moving the arm 11, as shown ing, practically, as a fulcrum. The hub of block 24 is recessed for the rod 20, while a vertically-movable block 25 is slidingiy mounted in Ways above the rod 20, so as to yield under certain conditions and permit the rod 20 to rise in its bearings at this point. A spring 26 is arranged above the block 25 to return. the rod to its usual seat. This sliding block 25 is preferably made in two pieces connected together by machine-screws for wellunderstood reasons.

The operation of the tripping-dog is as follows: The shaft 22 is designed to rotate in the direction of the arrow a. I will state here that the sparking device is to be used on an engine designed to run in one direction and is not adapted to a reversible engine, but could be used on a reversible engine if duplicated, as is well understood. In rotating in the direction of the arrow at the shaft 22, through its rod 20, fulcrumed in the oscillating block 24, will cause the lower end of the dog 19 to travel in the path indicated by the dot-and-dash line, Fig. 2, and in the direction of the arrow b. It will be seen that in its upper arc of movement the end of the dog will pass over the extension on arm 11 and then move down, so that on its lower arc of movement traveling in the direction of the arrow 0 it will pick up the arm 11 and carry said arm with it in an outward direction until the point of intersection between the lower arc of movement and the arc of movement of the arm 11 is reached. This intersectionpoint is indicated at d, and it is here that the arm 11 is released, so as to'move inwardly under the impelling action of its springs to snap the contact 6 away from contact 3. From the above it will be seen that the lower end of the dog travels in an elliptical path whose upper arc is above the end of arm 11, while said arm is in the path of the lower arc.

While, as stated before, the engine to which my improved sparking device is applied is designed to run in one direction,it sometimes happens, especially in starting the engine,

that it will kick back or run in a reverse direction, making several back strokes. It is obvious that under such. conditions the inward movement of the dog on the lower arc would engage the upper end of arm 11 in its path and something would have to give way. I provide the yielding block 25 to meet such a contingency, and when the dog on its backward movement engages the end of arm 11 its cam-face will force it upwardly and permit it to ride over the upper end of said arm, the block 25 rising in its ways to permit this. As soon. as the dog passes the upper end of arm 11 the spring 26 will force the rod 20 and its carried dog back to normal position in readiness to operate the arm 11 when the an inwardly-opening check-valve.

I am aware that minor changes in the construction, arrangement, and combination .of the several parts of my device can be made and substituted for those herein shown and described without in the least departing from the nature and principle of my invention.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is-

1. In a sparking device, the combination with a fixed contact and a movable contact arranged inside the cylinder, of a shaft upon which the movable contact is mounted, said shaft extending outside the cylinder, an arm fixed on the outer end of said shaft, an extension 8 on said arm, an independently-movable arm loosely mounted on said shaft, and having an extension 17 cooperating with the fixed arm, a tension-spring connecting the extension 8 and the movable arm, and a spring whose energies are constantly exerted to force the loosely-mounted arm to its home position; substantially as described.

2. In a sparking device, the combination of a fixed and a movable contact, a rock-shaft upon which the movable contact is mounted, an arm fixed to said rock-shaft, a lateral projection on said arm, an insulation-buffer for said arm, an independent arm loosely mounted on said shaft and cooperating with said projection, a tension-spring connecting said two arms, a revoluble crank-pin, a rod pivotblock in which said rod is slidingly f ulcru med,

yielding means for permitting said rod to rise in its bearing in said block, and a dog carried by said rod cooperating with said looselymounted arm; substantially as described.

3. In a sparking device, the combination with a fixed and a movable contact, means for operating the movable contact comprising a revoluble crank-pin, a rod pivotally carried by said crank-pin, an oscillating block in which said rod is slidingly fulcrumed, yielding means for permitting said rod to rise in its bearing in said block, and a dog carried by said rod; substantially as described.

4. In a sparking device, the combination with a fixed and a movable contact, of a swinging arm for operating'the movable contact, a rod, a dog on said rod, means for causing said dog to travel in an elliptical path, and an oscillating block forming a yielding bearing for said rod permitting the dog to ride over the with a fixed and movable contact, of an arm for operating the movable contact, an oscillating block, a rod slidingly mounted in said block, a yielding bearing for said rod, and a dog adjustably mounted on said rod and cooperating with said arm; substantially as described.

In testimony whereof I hereunto afilx my signature, in the presence of two witnesses,

this 6th day of February, 1903.

JOHN S. THURMAN.

Witnesses:

F. R. CORNWALL, GEORGE BAKEWELL. 

